Some consumers require complete control of the regulator and can't
tolerate sharing it with other consumers, most commonly because they need
to have the regulator actually disabled so can't have other consumers
forcing it on. This new regulator_get_exclusive() API call allows these
consumers to explicitly request this, documenting the assumptions that
they are making.

In order to simplify coding of such consumers the use count for regulators
they request is forced to match the enabled state of the regulator when
it is requested. This is not possible for consumers which can share
regulators due to the need to keep track of the ownership of use counts.

A new API call is used rather than an additional argument to the existing
regulator_get() in order to avoid merge headaches with driver code in
other trees.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NLiam Girdwood <lrg@slimlogic.co.uk>

Add a basic mechanism for regulators to report the discrete
voltages they support:  list_voltage() enumerates them using
selectors numbered from 0 to an upper bound.

Use those methods to force machine-level constraints into bounds.
(Example:  regulator supports 1.8V, 2.4V, 2.6V, 3.3V, and board
constraints for that rail are 2.0V to 3.6V ... so the range of
voltages is then 2.4V to 3.3V on this board.)

Export those voltages to the regulator consumer interface, so for
example regulator hooked up to an MMC/SD/SDIO slot can report the
actual voltage options available to cards connected there.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Acked-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NLiam Girdwood <lrg@slimlogic.co.uk>

Remove deceased email address and update to new address. Also update
website details in MAINTAINERS with correct page.
Signed-off-by: NLiam Girdwood <lrg@slimlogic.co.uk>

Regulator: Push lock out of _notifier_call_chain and into caller functions
(side effect of fixing deadlock in regulator_force_disable)
+ Add a voltage changed event.
Signed-off-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NLiam Girdwood <lrg@slimlogic.co.uk>

Remove kerneldoc warnings that don't relate to missing documentation,
mostly by renaming parameters in the documentation to match their
actual names.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NLiam Girdwood <lrg@slimlogic.co.uk>

Add support to allow consumer device drivers to control their regulator
power supply.

This uses a similar API to the kernel clock interface in that consumer
drivers can get and put a regulator (like they can with clocks atm) and
get/set voltage, current limit, mode, enable and disable. This should
allow consumers complete control over their supply voltage and current
limit. This also compiles out if not in use so drivers can be reused in
systems with no regulator based power control.
Signed-off-by: NLiam Girdwood <lg@opensource.wolfsonmicro.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>